FAA jack of all trades, no FCC endorsement needed for my first equivalent to B2 placement. I was hired as a blue water to avionics tech. Have since built a resume heavy on the avionics/systems side. The parts changers and the avionics installers are mostly in the MRO environment or in airline hangar environments. The more you desire to troubleshoot a problem these days the more you need to have avionics skills. The modern B1 is still similar to the most basic of line mechanics (changing tires and servicing an aircraft).
The B2 to the FAA is a combined breed of line techs for some airlines or in an avionics shop for others.
Since then the FCC endorsement is just about gone, hell most "avionics specialists" or self proclaimed, are ex military persons who know little about aircraft that have training on electronics.
In the FAA world, a need for a balanced training and experience history is the most desirable.